Capnoxygen masks

ABSTRACT

An oxygen mask configured for CO2 sampling and oxygen delivery, the oxygen mask having an oxygen inlet, a nasal breath-sampling element and a breath sampling port configured to receive breath samples, sampled by the breath-sampling element, wherein the breath-sampling element is configured to reduce dilution of exhaled breath by the delivered oxygen.

This application claims the benefit of U.S. Provisional Application Ser.No. 62/448,468 filed Jan. 20, 2017, the content of which is incorporatedherein by reference in its entirety for all purposes.

TECHNICAL FIELD

The present disclosure generally relates to the field of breathmonitoring, specifically to CO₂ sampling alongside oxygen delivery.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

The body needs oxygen to function properly and receives oxygen via thelungs to be metabolized in all cells of the body. Conditions affectingthe lungs, such as chronic obstructive pulmonary disease (COPD), requireoxygen therapy to get adequate oxygenation.

Nasal cannulas are capable of delivering oxygen at relatively lowconcentrations (typically between 24 to 40%) and at a relatively lowflow rates (6 LPM). Nasal cannulas are, therefore, most often onlysuitable for patients with rather minor breathing problems. Oxygenmasks, on the other hand, are capable of delivering oxygen at higherconcentrations (40 to 60%) at relatively high flow rates between (10 to15 LPM) and are, therefore, more suitable for patients with more severebreathing problems.

SUMMARY

Oxygen masks are often incompatible with CO₂ sampling primarily due todilution of the breath sample by delivered oxygen, and due torebreathing.

Advantageously, the capnoxygen masks disclosed herein are configured toprovide high quality CO₂ monitoring alongside delivery of oxygen at highflow rates and concentrations.

According to some embodiments, there is provided a double-layeredcapnoxygen mask having a first compartment configured to receive highconcentrations of oxygen for delivery to a patient and a secondcompartment configured for CO₂ sampling.

Advantageously, the double compartment capnoxygen mask providescomfortable wearing, reduced rebreathing, and oxygen delivery at highflow rates, along with high quality CO₂ monitoring. This is achieved byforming a sampling compartment in part of the mask closest to thepatient, the sampling compartment designated to enable non-diluted CO₂sampling. The outer compartment of the double compartment capnoxygenmask receives oxygen for delivery to the patient and is also referred toherein as the oxygen compartment.

According to some embodiments, the wall separating the compartments mayinclude a plurality of perforations, optionally distributed throughoutthe wall surface, through which oxygen can reach the internalcompartment. Advantageously, the perforations enable delivery of oxygenfrom multiple directions and facilitate dispersed rather than jet flowdelivery of oxygen, thereby reducing rebreathing.

According to some embodiments, there is provided a capnoxygen maskincluding nasal prongs, through which exhaled air may be sampled.Advantageously, the nasal prongs are configured to provide high qualityCO₂ monitoring alongside oxygen delivery at high flow rates andconcentrations.

According to some embodiments, the nasal prongs may be semi-rigid nasalprongs fitted to be in front of the nasal openings. According to someembodiments, the capnoxygen mask may further include a sampling port,for example, on the nose-bridge outside the mask. The sampling port maybe connected to the nasal prongs, thereby allowing direct and efficienttransfer of exhaled breath outside the mask, while minimally interferingwith patient comfort. According to some embodiments, the nasal prongsmay be attached to external adjustment handles configured to enableadjustment of the nasal prongs' position. Advantageously, the adjustmenthandles may ensure optimal CO₂ monitoring and patient comfort forsubjects with varying facial proportions.

According to some embodiments, there is provided a capnoxygen maskincluding a nasal trap, through which exhaled air may be sampled. Thenasal trap is configured to ensure high quality CO₂ monitoring alongsideoxygen delivery at high flow rates and concentrations. This is achievedby physical separation of the breath sampling area from the oxygendelivered.

According to some embodiments, the capnoxygen mask may include amanifold structure including an oxygen inlet, a sampling port, and asampling tubing directly connected to the nasal trap. Advantageously,the manifold structure may be configured to enable oxygen, deliveredthrough the oxygen inlet, to be dispersed within the manifold structure,thereby ensuring an essentially equal distribution of the oxygenthroughout the mask.

According to some embodiments, there is provided a breath samplingcannula, including two sampling tubes, each configured for insertioninto a subject's nostril. Advantageously, the sampling tubes includemagnets, which are sufficiently strong to keep the cannula attachedto/clipped on the subject's nose septum, while causing minimalinterference with patient comfort. The breath sampling cannula isadvantageously aligned with the patient's nose thereby reducing dilutionas well as increasing patient comfort when worn in conjunction withoxygen masks.

According to some embodiments, there is provided a capnoxygen maskconfigured for CO₂ sampling and oxygen delivery, the capnoxygen maskhaving an oxygen inlet, a nasal breath-sampling element configured toreduce dilution of exhaled breath by the delivered oxygen, and a breathsampling port configured to receive breath samples, sampled by thebreath-sampling element.

According to some embodiments, the nasal breath-sampling element may bemolded on or otherwise attached to an internal side of the capnoxygenmask.

According to some embodiments, the capnoxygen mask may further includean oral sampling element configured for sampling exhaled breath from asubject's mouth, when in use.

According to some embodiments, the nasal breath-sampling element may beor may include two nasal prongs fitted within the mask so as to bepositioned within or below a subject's nostrils, when in use. Accordingto some embodiments, the two nasal prongs may be connected to anadjustment handle, the adjustment handle located outside the capnoxygenmask. According to some embodiments, movement of the adjustment handlemay enable adjusting a position of the two nasal prongs within thecapnoxygen mask.

According to some embodiments, the nasal breath-sampling element may beor may include a nasal trap. The nasal trap may be shaped to isolate asubject's nasal exhale area from oxygen delivered to the capnoxygenmask. According to some embodiments, the sampling port may be in fluidflow connection with the nasal trap.

According to some embodiments, the capnoxygen mask may further include amanifold structure, including the oxygen inlet and the breath samplingport. According to some embodiments, oxygen delivered through the oxygeninlet may be dispersed within the manifold. According to someembodiments, oxygen dispersed within the manifold may reach an area ofthe capnoxygen mask surrounding the nasal trap. According to someembodiments, the nasal trap may include a plurality of oxygen supplyperforations configured to allow oxygen dispersed by the manifoldstructure to enter the nasal trap.

According to some embodiments, the nasal breath-sampling element may beor include an inner sampling compartment. According to some embodiments,the capnoxygen mask may include an inner wall separating the capnoxygenmask into an inner sampling compartment and an outer oxygen deliverycompartment. According to some embodiments, the wall may include aplurality of oxygen supply perforations through which oxygen can reachthe inner sampling compartment. According to some embodiments, the innersampling compartment may include two nasal prongs fitted within theinner sampling compartment so as to be positioned within or below asubject's nostrils, when in use.

According to some embodiments, the capnoxygen mask may further include abreath sampling tube attached to the breath sampling port.

According to some embodiments, there is provided a breath samplingcannula having a first nasal prong and a first tube; the first tubebeing in fluid flow communication with the first nasal prong; and asecond nasal prong and a second tube, the second tube being in fluidflow communication with the second nasal prong. According to someembodiments, the first tube and/or first nasal prong may include a firstmagnet and the second tube and/or second nasal prong may include asecond magnet. According to some embodiments, the magnetic force betweenthe first and second magnets enables grasping a nose septum on oppositesides thereof.

According to some embodiments, the first and second magnets compriserare-earth magnets. According to some embodiments, the first and secondmagnets may be or may include neodymium magnets.

According to some embodiments, the breath sampling cannula may furtherinclude a sampling tube and a Y-junction interconnecting the first tube,the second tube and the sampling tube. According to some embodiments,the Y-junction may be sized and shaped to be pulled through a dedicatedhole of an oxygen mask.

According to some embodiments, there is provided a capnoxygen systemincluding: a breath sampling cannula having a first nasal prong and afirst tube, the first tube being in fluid flow communication with thefirst nasal prong; a second nasal prong and a second tube, the secondtube being in fluid flow communication with the second nasal prong; anda Y-junction interconnecting the first tube and the second tube with abreath sampling line. According to some embodiments, the first tubeand/or first nasal prong may include a first magnet and the second tubeand/or second nasal prong may include a second magnet. According to someembodiments, the magnetic force between the first and second magnetsenables grasping a nose septum on opposite sides thereof. According tosome embodiments, the capnoxygen system further includes an oxygen maskhaving an aperture configured to receive the Y-junction.

According to some embodiments, the first and second magnets may be ormay include rare-earth magnets.

Certain embodiments of the present disclosure may include some, all, ornone of the above advantages. One or more technical advantages may bereadily apparent to those skilled in the art from the figures,descriptions and claims included herein. Moreover, while specificadvantages have been enumerated above, various embodiments may includeall, some or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples illustrative of embodiments are described below with referenceto figures attached hereto. In the figures, identical structures,elements or parts that appear in more than one figure are generallylabeled with a same numeral in all the figures in which they appear.Alternatively, elements or parts that appear in more than one figure maybe labeled with different numerals in the different figures in whichthey appear. Dimensions of components and features shown in the figuresare generally chosen for convenience and clarity of presentation and arenot necessarily shown in scale. The figures are listed below.

FIG. 1A shows a side view of a capnoxygen mask with nasal prongs,according to some embodiments;

FIG. 1B shows a front view of a capnoxygen mask with nasal prongs,according to some embodiments;

FIG. 2 shows a side view of a capnoxygen mask with nasal prongs andadjustment handles, according to some embodiments;

FIG. 3 shows a side view of a capnoxygen mask with nasal trap, accordingto some embodiments;

FIG. 4A shows a side view of a double layered capnoxygen mask, accordingto some embodiments;

FIG. 4B, shows a double layered capnoxygen mask viewed from the inside,according to some embodiments;

FIG. 5A shows a breath sampling cannula including magnets, according tosome embodiments;

FIG. 5B shows the breath sampling cannula including magnets of FIG. 5Awhen used in conjunction with an oxygen mask, according to someembodiments;

FIG. 6 shows an outline of the test setup used for evaluating thecapnoxygen mask disclosed herein;

FIG. 7 shows the CO₂ waveforms obtained when evaluating a standard nasalcannula and oxygen delivery mask (POM M1);

FIG. 8A shows the CO₂ waveforms obtained when evaluating the capnoxygenmask with nasal prongs depicted in FIG. 1A and FIG. 1B at a 5 LPM oxygenflow rate;

FIG. 8B shows the CO₂ waveforms obtained when evaluating the capnoxygenmask with nasal prongs depicted in FIG. 1A and FIG. 1B at a 15 LPMoxygen flow rate;

FIG. 9A shows the CO₂ waveforms obtained when evaluating the capnoxygenmask with nasal trap depicted in FIG. 3 at a 5 LPM oxygen flow rate;

FIG. 9B shows the CO₂ waveforms obtained when evaluating the capnoxygenmask with nasal trap depicted in FIG. 3 at a 15 LPM oxygen delivery flowrate;

FIG. 10A shows the CO₂ waveforms obtained when evaluating the doublelayered capnoxygen mask depicted in FIG. 4A and FIG. 4B at a 5 LPMoxygen flow rate;

FIG. 10B shows the CO₂ waveforms obtained when evaluating the doublelayered capnoxygen mask depicted in FIG. 4A and FIG. 4B at a 15 LPMoxygen flow rate; and

FIG. 11 shows the CO₂ waveforms obtained when evaluating a standardoxygen mask alone or in conjunction with the breath sampling cannuladepicted in FIG. 5A and FIG. 5B.

DETAILED DESCRIPTION

In the following description, various aspects of the disclosure will bedescribed. For the purpose of explanation, specific configurations anddetails are set forth in order to provide a thorough understanding ofthe different aspects of the disclosure. However, it will also beapparent to one skilled in the art that the disclosure may be practicedwithout specific details being presented herein. Furthermore, well-knownfeatures may be omitted or simplified in order not to obscure thedisclosure. Additionally, it is to be explicitly understood that anycombination of any one or more of the disclosed embodiments may beapplicable and is within the scope of the disclosure.

The present disclosure generally relates to the field of breathmonitoring, specifically to CO₂ sampling alongside oxygen delivery usingoxygen masks.

According to some embodiments, there is provided a capnoxygen maskconfigured for CO₂ sampling, while at the same time administeringoxygen. The capnoxygen mask includes an oxygen inlet, a nasalbreath-sampling element and a breath sampling port configured to receivebreath samples sampled by the breath-sampling element, wherein thebreath-sampling element is configured to reduce dilution of exhaledbreath by the delivered oxygen.

As used herein, the term “capnoxygen mask” may refer to a maskconfigured to provide oxygen to a subject, while allowing efficient andmedically significant sampling of the exhaled carbon dioxide. Accordingto some embodiments, the capnoxygen mask may cover the nose and mouth(oral nasal mask) or the entire face (full-face mask). The mask may bemade of plastic, silicone, rubber or any other suitable material.According to some embodiments, the capnoxygen mask may be anon-rebreather mask having an attached reservoir bag, that connects toan external oxygen tank or bulk oxygen Supply system.

As used herein, the term “breath-sampling element” may refer to anyelement configured to facilitate measuring CO₂ concentrations in apatient's breath in a sufficiently reliably manner to obtain asatisfying waveform shape. Various breath-sampling elements may beenvisaged, as further disclosed herein. According to some embodiments,the breath-sampling element may be an integral part of the capnoxygenmask. For example, the breath-sampling element may be molded with orotherwise attached to an inner side of the capnoxygen mask, i.e., theside of the capnoxygen mask facing the patient. Alternatively, thebreath-sampling element may be a separate element configured to beincorporated and/or attached to existing oxygen masks as a modularelement, so as to form an integral unit therewith.

As used herein, the term “reduced dilution” with regards to thebreath-sampling element, may refer to the breath-sampling element beingand/or having structural features, which sufficiently prevent dilutionof the subject's exhaled breath to obtain a satisfying waveform.

As used herein the term “satisfying waveform” may refer to a waveformhaving a less than 10%, less than 5%, less than 1% deviation from thewaveform which would have been obtained would the breath sampling beentirely undiluted by delivered oxygen. Each possibility is a separateembodiment.

As used herein, the terms “subject” and “patient” may be usedinterchangeably and may refer to any individual undergoing CO₂monitoring during oxygen delivery, using oxygen delivery masks.

According to some embodiments, the capnoxygen mask may further includean oral sampling element, such as, but not limited to, an oral prong,configured for sampling from a subject's mouth, when in use.

According to some embodiments, the capnoxygen mask may further include abreath sampling tube attached to and/or attachable to the breathsampling port. Additionally or alternatively, the breath sampling portmay include a connector configured for connection to a breath samplingtube.

According to some embodiments, the breath sampling port may bepositioned on a nose-bridge outside of the capnoxygen mask. According tosome embodiments, the breath sampling port may be positioned on part ofthe mask being beneath and/or in front of the subject's nose, mouth orcheek, when in use. Each possibility is a separate embodiment.

According to some embodiments, the nasal breath-sampling element may beand/or may include two nasal prongs fitted within the mask so as to bepositioned within or below a subject's nostrils, when in use. Accordingto some embodiments, the nasal prongs may be an integral part of thecapnoxygen mask, e.g. molded with the mask. Alternatively, the oralprongs may be attached to the capnoxygen mask, or parts thereof, so asto form an integral part therewith. This advantageously provides asingle integrated unit, which is much more comfortable to wear than thebulky simultaneous wearing of an oxygen mask for oxygen delivery and astand-alone breath sampling cannula for breath monitoring.

According to some embodiments, the nasal prongs may be connected to anadjustment handle, located outside the oxygen mask and enablingadjustment of the position of the nasal prongs within the oxygen mask.According to some embodiments, the adjustment handle may be configuredto adjust the distance between the nasal prongs. Additionally oralternatively, the adjustment handle may be configured to adjust theangle of the nasal prongs relative to the capnoxygen mask. Additionallyor alternatively, the adjustment handle may be configured to adjust thedistance between the nasal prongs and the subject's nostrils and thusthe depth of their insertion into the subject's nostrils.

According to some embodiments, the nasal breath-sampling element may beor may include a nasal trap, shaped to fit around a subject's nose. Thenasal trap may thus isolate the subject's nasal exhale area from oxygendelivered to the capnoxygen mask. According to some embodiments, thesampling port may be in fluid flow connection with the nasal trap.According to some embodiments, the nasal trap may be directly connectedto the sampling port.

According to some embodiments, the nasal trap may include a plurality ofoxygen supply perforations through which oxygen may enter the nasaltrap. As used herein, the term “plurality”, when referring to oxygensupply perforations, may include more than 5 oxygen supply perforations,more than 10 oxygen supply perforations, more than 20 oxygen supplyperforations, or any other suitable number of oxygen supplyperforations. Each possibility is a separate embodiment. According tosome embodiments, the plurality of oxygen supply perforations may bedispersed throughout the surface of the nasal trap, such that thedelivered oxygen enters the nasal trap from multiple directions.Advantageously, the perforations generate dispersed rather than jet flowoxygen delivery, thereby reducing dilution of the sampled exhaled breathby the delivered oxygen as well as rebreathing.

Additionally or alternatively the capnoxygen mask may include a manifoldstructure including the oxygen inlet and the breath sampling port.According to some embodiments, the manifold structure may include asampling tubing connecting the nasal trap to the breath sampling port.According to some embodiments, oxygen delivered through the oxygen inletmay be dispersed within the manifold structure and around the samplingtubing. From the manifold structure, the oxygen may be delivered to thenasal trap at a dispersed rather than jet flow, thereby reducingdilution of the sampled exhaled breath by the delivered oxygen as wellas rebreathing.

According to some embodiments, the capnoxygen mask may be a doublelayered capnoxygen mask. According to some embodiments, the capnoxygenmask may include a wall inside the mask, generating an innerlumen/compartment configured for sampling, also referred to herein as a“sampling compartment”, and an outer oxygen delivery lumen/compartment,also referred to herein as an “oxygen compartment”. According to someembodiments, the wall may include a plurality of oxygen supplyperforations through which oxygen can reach the inner samplingcompartment. Advantageously, the perforations generate dispersed ratherthan jet flow oxygen delivery, thereby reducing dilution of the sampledexhaled breath by the delivered oxygen as well as rebreathing.

According to some embodiments, the sampling compartment may includenasal prongs (e.g. two nasal prongs) fitted within the inner samplingcompartment so as to be positioned within or below a subject's nostrilswhen in use, as essentially described herein.

According to some embodiments, there is provided a breath samplingcannula including a first nasal prong and a first tube, the first tubebeing in fluid flow communication with the first nasal prong; a secondnasal prong and a second tube the second tube being in fluid flowcommunication with the second nasal prong; wherein the first tubeincludes a first magnet and the second tube includes a second magnet,and wherein a magnetic force between the first and the second magnetsenables grasping a subject's nose septum on opposite sides thereof, whenin use.

According to some embodiments, the (first and/or second) nasal prong andthe (first and/or second) tubes may be coextensive, and the nasal prongmay refer to and/or include the part of the tube which is inserted intothe patient's nostrils and/or the part of the tube (the distal endthereof) proximate to the subject's nostrils, when in use.Alternatively, the nasal prong may be a separate element and may have asmaller diameter than the tube, in which case the nasal prong is moldedon/with or otherwise attached to the tube, so as to be in fluidcommunication therewith.

According to some embodiments, the breath sampling cannula may furtherinclude a breath sampling tube and a Y-junction, the Y-junctioninterconnecting the first tube, the second tube and the breath samplingtube, such that exhaled breath can flow from the first and second tubesto the breath sampling tube, and from there to the monitor (e.g. acapnography).

According to some embodiments, the breath sampling cannula mayadvantageously be devoid of attachment means (such as straps configuredto be worn around the subject's ears) and may thus be worn inconjunction with an oxygen mask without causing patient discomfort.According to some embodiments, the Y-junction may be sized and shaped tobe pulled through a hole of an oxygen mask.

According to some embodiments, the magnets may be sufficiently strong tokeep the cannula attached to/clipped on the subject's nose septum,without interfering with patient comfort. According to some embodiments,the magnets may be or may include rare-earth magnets. According to someembodiments, the rare-earth magnets may be or may include neodymiummagnets (e g. neodymium balls 4-5 mm). According to some embodiments,the rare-earth magnets may be or may include samarium-cobalt magnets.According to some embodiments, the magnets may be or may include ferriteor ceramic magnets. According to some embodiments, the magnets mayproduce a magnetic field, which exceeds 1.2 tesla, 1.25 tesla, 1.3tesla, 1.4 tesla or 1.5 tesla. Each possibility is a separateembodiment. According to some embodiments, the magnets may be coated ormay be a material suitable to provide protection and/or reduce thevulnerability of the magnets.

Examples illustrative of embodiments are described below with referenceto figures attached hereto. Combinations of the below embodiments areenvisaged and are within the scope of this disclosure. For example,certain elements described/depicted in one embodiment/figure, e.g. nasalprongs, may be included in other figures, despite not being depicted.

Reference is now made to FIG. 1A and FIG. 1B, which show side and frontviews of a capnoxygen mask 100 with nasal prongs 110, according to someembodiments. Nasal prongs 110 may be semi-rigid and arranged to be infront of a subject's nasal openings 102. Nasal prongs 110 are externallyconnected to a sampling port 120, here positioned on a nose-bridge 122outside of the capnoxygen mask 100; however, alternative positioning ofthe sampling port is also envisaged, as further elaborated herein, andis thus within the scope of the disclosure. The capnoxygen mask 100 mayoptionally further include an oral sampling port (not shown) configuredfor sampling from the subject's mouth 104.

Reference is now made to FIG. 2, which shows a side views of acapnoxygen mask 200 with nasal prongs 210 and adjustment handles 212,according to some embodiments. Adjustment handles 212 are configured toadjust the position of nasal prongs 210 so as to ensure optimal CO₂monitoring and patient comfort in subjects with varying facialproportions. Nasal prongs 210 are essentially similar to nasal prongs110 and may be semi-rigid and arranged to be in front of a subject'snasal openings 202. Nasal prongs 210 are externally connected to asampling port 220, here positioned below the subject's nose 206 outsidethe capnoxygen mask 200; however, alternative positioning of thesampling port is also envisaged, as further elaborated herein, and isthus within the scope of the disclosure. The capnoxygen mask 200 mayoptionally further include an oral sampling port (not shown) configuredfor sampling from the subject's mouth 204.

Reference is now made to FIG. 3, which shows a side view of a capnoxygenmask 300 with nasal trap 310, according to some embodiments. Nasal trap310 is optionally adjustable and is configured to fit the patient's facegeometry so as to surround the patient's nose 306. As a result, anisolated breath sampling area is formed around nose 306, which preventsdilution of exhaled breath by delivered oxygen. The capnoxygen mask 300further includes a manifold structure 340 including a sampling port 320,sampling tubing 342, configured to connect the nasal trap 310 tosampling port 320, and an oxygen inlet 344. Oxygen, delivered throughthe oxygen inlet 344, is dispersed within manifold structure 340 aroundthe sampling tubing 342. From manifold structure 340, oxygen may bedelivered to the nasal trap 310 at a dispersed flow rather than a jetflow, thereby reducing rebreathing as well as dilution of the sampledexhaled breath by the delivered oxygen.

Reference is now made to FIG. 4A and FIG. 4B, which show a doublelayered capnoxygen mask 400, according to some embodiments. The doublelayered capnoxygen mask 400 generates a double compartment mask,including a first inner compartment 412 (closest to the patient, whenworn) configured to enable non-diluted CO₂ sampling, and a second outercompartment 452 configured to receive oxygen from oxygen inlet 444. Awall 460 separating the first inner compartment 412 and the second outercompartment 452 includes a plurality of perforations 470, through whichoxygen can reach first inner compartment 412. The perforations 470 maybe positioned throughout the surface of the wall 460, thereby enablingdelivery of oxygen from multiple directions and at a dispersed ratherthan jet flow. The first inner compartment 412 may further include nasalprongs 410 configured to further decrease the dilution of the patient'sexhaled breath with the delivered oxygen. The nasal prongs 410 areconnected to sampling port 420, as essentially described herein.

Reference is now made to FIG. 5A and FIG. 5B, which show a breathsampling cannula 500 including magnets 550 a and 550 b, according tosome embodiments. The breath sampling cannula 500 includes a first nasalprong 510 a and a first tube 520 a being in fluid flow communication,and a second nasal prong 510 b and a second tube 520 b being in fluidflow communication. The tubes 520 a and 520 b are further in fluid flowcommunication with a Y-junction 522 and a breath sampling tube 524,through which exhaled breath may reach the breath monitor (not shown).The magnet 550 a is positioned on the nasal prong 510 a and/or on thetube 520 a, and the magnet 550 b is positioned on the nasal prong 510 band/or on the second tube 520 b, in such a manner that the magneticforce of the magnets 550 a and 550 b (e.g. neodymium rare magnets)causes the nasal prongs 510 a and 510 b and/or the tube 520 a and thetube 520 b to grasp the nose septum 506 on opposite sides thereof, whenin use. The Y-junction 522 is sized and shaped to be pulled through adedicated hole 562 of oxygen mask 560 (FIG. 5B), thereby facilitatingefficient non-diluted CO₂ sampling alongside oxygen delivery, using anytype of oxygen mask.

Examples

Test Setup on Manikin

The test setup for the capnoxygen masks disclosed herein was built onthe basis of the Ingmar Medical Breath Simulator with mechanical lung,connected to a manikin head, connected to a capnograph, measuring maskperformance in terms of capnography within a defined set of breathingregimes and oxygen (air) flows. An outline of the test setup is shown inFIG. 6. Table 1 below specifies the elements of the system, as shown inFIG. 6.

TABLE 1 Figure elements ## Description 1 Laboratory Lung Model 2Humidifier + filter (optional) 3 Manikin head 4 Standard Cannula(reference) 5 Oxygen Mask being tested 6 Capnograph 7 Computer 8 TSIMass Flow Meter (up to 20 L/min) 9 Restrictor valve 10 Oxygen/Air gasreservoir 11 100% CO₂, with calibrated flow 12 MiniOx 3000 oxygen meter(optional)

The following settings were implemented:

-   -   Breath Mode=“Eupnea” (Normal breathing)    -   Compliance=50 mL/cmH2O    -   Restriction=20 cmH2O/L/s (Restrictor used=Rp20)    -   Offset (AKA Dead Space)=140 ml    -   Inhalation/exhalation (I/E) ratio=1/2        Procedure:    -   1. The reference setup (baseline) measurement was performed with        a nasal cannula (without mask) in order to calibrate the exhaled        CO₂ gas to receive a 35 mmHg CO₂ partial pressure on nasal        breathing.    -   2. The mask prototype was placed on the manikin head and the        EtCO₂ signal was measured through the sampling port at varying        oxygen/air flow rates (5 liters per minute (LPM) and 15 LPM),        tidal volumes (250-700 mL) and respiration rates (10-25 breaths        per minute (BPM)).    -   3. All results were recorded on a Capnostream20 capnograph.        In-Vivo Testing

The capnoxygen masks, disclosed herein, were tested in-vivo on a healthytest-subject, evaluating regular breathing at varying respiration ratesand oxygen/air flow (nasal breathing). A metronome was used to guide therespiration rate during the measurement. All results were recorded on aCapnostream20 capnograph and appropriate waveforms recorded.

Test Results

POM M1 Oxygen Mask

FIG. 7 depicts the CO₂ waveforms obtained using the reference setup(nasal cannula) as compared to a standard oxygen delivery mask (POM M1)at 500 ml tidal volume, 5 BPM respiratory rate and 5 LPM oxygen flow. Asseen from FIG. 7, using an oxygen mask causes dilution of the exhaledbreath, and, as a result, negatively affects the obtained waveform.

Capnoxygen Mask with Nasal Prongs

The capnoxygen mask includes nasal prongs, fitted to be in front of asubject's nasal openings and externally connected to the sampling porton the nose-bridge outside of the mask, as shown in FIG. 1A and FIG. 1B.

Measurement results, obtained when tested on a manikin according to thesetup described above, are shown in Table 2 and Table 3 below, and theCO₂ waveform, derived from the measurements, is shown in FIG. 8A andFIG. 8B, solid black line.

TABLE 2 Partial pressure CO₂ (mmHg) at 5 L LPM oxygen flow. Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 29 600 29 30 30 500 29 29 30 31 450 29 2930 31 400 29 28 29 30 350 29 29 29 30 300 29 29 29 30 250 32 29 30 31

TABLE 3 Partial pressure CO₂ (mmHg) at 15 L LPM oxygen flow Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 31 600 32 32 35 500 30 33 35 35 450 31 3235 36 400 32 32 35 36 350 32 32 35 37 300 33 34 35 38 250 35 35 35 39

As seen from Tables 2 and 3, partial pressure CO₂ values weresatisfyingly close to those obtained using the nasal cannula (35 mmHg)and are thus indicative of minimal dilution of the breath samples by thesupplied oxygen, whether delivered at low (5 LPM) or high (15 LPM) flow.

Table 4 below provides the in-vivo (test subjects) results, and FIG. 8Aand FIG. 8B provide the CO₂ waveforms obtained at 5 LPM and 15 LPMoxygen delivery, respectively.

TABLE 4 Partial pressure CO₂ (mmHg) at 5 and 15 L LPM oxygen flow. Flow(LPM) RR (BPM) 5 15 10 38 35 15 35 35 20 34 35 25 31 34

Surprisingly, the in-vivo measurement indicated an even lesser dilutionthan that obtained when performing the measurements on the manikin,probably due to inaccurate upper airway geometry and facial proportionof the manikin.

Capnoxygen Mask with Nasal Trap

The capnoxygen mask includes an internal adjustable nasal-add-on (nasaltrap) which may be adjusted to fit patient geometry, as shown in FIG. 3.

Measurement results, obtained when tested on a manikin according to thesetup described above, are shown in Table 5 and Table 6 below, and theCO₂ waveforms derived from the measurements are shown in FIG. 9A andFIG. 9B, solid black line.

TABLE 5 Partial pressure CO₂ (mmHg) at 5 L LPM oxygen flow. Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 34 600 34 34 35 500 32 35 34 35 450 32 3535 35 400 35 35 35 35 350 35 35 37 36 300 36 35 37 37 250 39 35 39 38

TABLE 6 Partial pressure CO₂ (mmHg) at 15 L LPM oxygen flow Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 32 600 31 32 32 500 32 32 32 35 450 32 3233 35 400 33 33 34 35 350 33 33 34 35 300 34 35 37 37 250 35 37 36 37

As seen from Tables 5 and 6, partial pressure CO₂ values weresatisfyingly close to those obtained using the nasal cannula (35 mmHg)and are thus indicative of minimal dilution of the breath samples by thesupplied oxygen, whether delivered at low (5 LPM) or high (15 LPM) flow.

Table 7 below provides the in-vivo (test subjects) results, and FIG. 9Aand FIG. 9B show the CO₂ waveforms obtained at 5 LPM and 15 LPM oxygendelivery, respectively.

TABLE 7 Partial pressure CO₂ (mmHg) at 5 and 15 L LPM oxygen flow. Flow(LPM) RR (BPM) 5 15 10 39 38 15 38 37 20 38 37 25 38 38

Surprisingly, the in-vivo measurement indicated an even lesser dilutionthan that obtained when performing the measurements on the manikin,probably due to inaccurate upper airway geometry and facial proportionof the manikin.

Double Layered Capnoxygen Mask

The double layered capnoxygen mask (shown in FIG. 4A and FIG. 4B)features a modified non-rebreather mask approach. The mask isdouble-layered, generating an internal space serving as an oxygendelivery manifold, configured to deliver a high concentration of O₂ tothe patient from all-around the face.

Measurement results, obtained when tested on a manikin according to thesetup described above, are shown in Table 8 and Table 9 below, and theCO₂ waveforms, derived from the measurements is shown in FIGS. 10A and10B, solid black line.

TABLE 8 Partial pressure CO₂ (mmHg) at 5 L LPM oxygen flow. Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 32 600 30 32 33 500 30 31 33 30 450 29 3135 35 400 30 31 32 35 350 30 31 32 35 300 31 32 32 35 250 32 34 32 34

TABLE 9 Partial pressure CO₂ (mmHg) at 15 L LPM oxygen flow Tidal VolumeRR (BPM) (mL) 10 15 20 25 700 25 600 25 25 26 500 25 25 25 26 450 25 2525 26 400 25 25 25 27 350 26 25 25 27 300 25 25 25 28 250 25 25 24 27

As seen from Table 8, partial pressure CO₂ values were satisfyinglyclose to those obtained using the nasal cannula (35 mmHg) and are thusindicative of minimal dilution of the breath samples by the suppliedoxygen when delivered at low (5 LPM). At the high (15 LPM) flow, thepartial pressure values obtained indicated dilution of the exhaledbreath by the delivered oxygen. This is probably due to the inaccurateupper airway geometry and facial proportion of the manikin.

Table 10 below provides the in-vivo (test subjects) results, and FIG.10A and FIG. 10B show the CO₂ waveforms obtained at 5 LPM and 15 LPMoxygen delivery, respectively.

TABLE 10 Partial pressure CO₂ (mmHg) at 5 and 15 L LPM oxygen flow. Flow(LPM) RR (BPM) 5 15 10 33 35 15 35 35 20 35 35 25 35 35

Surprisingly, the in-vivo measurement indicated absence of dilution andthus shows the ability of the double layered capnoxygen mask to providehigh quality CO₂ monitoring alongside oxygen delivery.

Standard Oxygen Mask in Conjunction with Breath Sampling Cannula withMagnets

CO₂ waveforms were also measured using a standard oxygen mask alone orin conjunction with the breath sampling cannula with magnets, depictedin FIG. 5A and FIG. 5B. The test was performed at oxygen flows of 5 LPMand 15 LPM and showed reduced dilution and satisfying waveform shape, asseen in FIG. 11.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” or “comprising”, whenused in this specification, specify the presence of stated features,integers, steps, operations, elements, or components, but do notpreclude or rule out the presence or addition of one or more otherfeatures, integers, steps, operations, elements, components, or groupsthereof.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specificationdiscussions utilizing terms such as “processing”, “computing”,“calculating”, “determining”, “estimating”, or the like, refer to theaction and/or processes of a computer or computing system, or similarelectronic computing device, that manipulate and/or transform datarepresented as physical, such as electronic, quantities within thecomputing system's registers and/or memories into other data similarlyrepresented as physical quantities within the computing system'smemories, registers or other such information storage, transmission ordisplay devices.

Embodiments of the present techniques may include apparatuses forperforming the operations herein. This apparatus may be speciallyconstructed for the desired purposes, or it may comprise a generalpurpose computer selectively activated or reconfigured by a computerprogram stored in the computer. Such a computer program may be stored ina computer readable storage medium, such as, but not limited to, anytype of disk, including floppy disks, optical disks, CD-ROMs,magnetic-optical disks, read-only memories (ROMs), random accessmemories (RAMs) electrically programmable read-only memories (EPROMs),electrically erasable and programmable read only memories (EEPROMs),magnetic or optical cards, or any other type of media suitable forstoring electronic instructions, and capable of being coupled to acomputer system bus.

The processes and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct a more specializedapparatus to perform the desired method. The desired structure for avariety of these systems will appear from the description below. Inaddition, embodiments of the present invention are not described withreference to any particular programming language. It will be appreciatedthat a variety of programming languages may be used to implement theteachings of the inventions, as described herein.

The techniques may be described in the general context ofcomputer-executable instructions, such as program modules, beingexecuted by a computer. Generally, program modules include routines,programs, objects, components, data structures, and so forth, whichperform particular tasks or implement particular abstract data types.The invention may also be practiced in distributed computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network. In a distributed computingenvironment, program modules may be located in both local and remotecomputer storage media including memory storage devices.

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,additions and sub-combinations thereof. It is therefore intended thatthe following appended claims and claims hereafter introduced beinterpreted to include all such modifications, additions andsub-combinations as are within their true spirit and scope.

The techniques presented and claimed herein are referenced and appliedto material objects and concrete examples of a practical nature thatdemonstrably improve the present technical field and, as such, are notabstract, intangible or purely theoretical. Further, if any claimsappended to the end of this specification contain one or more elementsdesignated as “means for [perform]ing [a function] . . . ” or “step for[perform]ing [a function] . . . ”, it is intended that such elements areto be interpreted under 35 U.S.C. 112(f). However, for any claimscontaining elements designated in any other manner, it is intended thatsuch elements are not to be interpreted under 35 U.S.C. 112(f).

The invention claimed is:
 1. An oxygen mask configured for CO₂ samplingand oxygen delivery, the oxygen mask comprising: an oxygen inlet, anasal breath-sampling element configured to reduce dilution of exhaledbreath by the delivered oxygen, wherein the nasal breath-samplingelement comprises an inner sampling compartment, wherein the oxygen maskcomprises an inner wall separating the oxygen mask into the innersampling compartment and an outer oxygen delivery compartment andwherein the inner wall comprises a plurality of oxygen supplyperforations through which oxygen can reach the inner samplingcompartment; and a breath sampling port configured to receive breathsamples, sampled by the breath sampling element.
 2. The oxygen mask ofclaim 1, wherein the nasal breath- sampling element is molded on, orotherwise attached to, an internal side of the oxygen mask.
 3. Theoxygen mask of claim 1, further comprising an oral sampling elementconfigured for sampling exhaled breath from a subject's mouth when inuse.
 4. The oxygen mask of claim 1, wherein the nasal breath- samplingelement comprises two nasal prongs fitted within the mask so as to bepositioned within or below a subject's nostrils when in use.
 5. Theoxygen mask of claim 4, wherein the two nasal prongs are connected to anadjustment handle, the adjustment handle located outside the oxygenmask, wherein movement of the adjustment handle enables adjusting aposition of the two nasal prongs within the oxygen mask.
 6. The oxygenmask of claim 1, wherein the inner sampling compartment comprises twonasal prongs fitted within the inner sampling compartment so as to bepositioned within or below a subject's nostrils, when in use.
 7. Theoxygen mask of claim 1, further comprising a breath sampling tubeattached to the breath sampling port.